New clues are emerging about the disappearance of Iowa college student Mollie Tibbetts, who was last seen out on a jog July 18.

A neighbor reported seeing a suspicious black SUV circling the neighborhood between 11:30 p.m. the night Tibbetts was last seen and 1 a.m. the following morning, according to Fox News.

The woman, who lives about a block from the house where Tibbetts was staying while she was dog-sitting for her boyfriend, said she reported the suspicious activity to the FBI.

Investigators have explored more than 200 leads in the search for the University of Iowa college student since the investigation began more than two weeks ago.

On Sunday, they returned to speak with an area pig farmer who has been repeatedly questioned in the case. Sunday's visit, which only lasted five to 10 minutes, was the third visit by investigators, according to Fox News.

The pig farmer, Wayne Cheney, had previously told the news channel he was not involved in the disappearance and said the FBI searched his home and a portion of his property for several hours last week. They also looked through his cell phone.

Cheney has declined to take a polygraph, Fox News reported, but said he would allow investigators to search his entire property because he had nothing to hide.

Cheney told WHO-TV he did not know the missing college student, but was taken by investigators in for questioning.

"I don't know who those two were but they took me down to the fire station Tuesday and questioned me for two hours," he told WHO-TV. "I don't remember what they asked me."

He said he thought the questioning was a "waste of time."

Investigators have said they can't comment on whether or not Cheney has been cleared as a suspect, according to WHO-TV.

Iowa court records show Cheney has pleaded guilty to stalking in two separate incidents. One plea was in 2009 while the other was in 2014.

Also on Sunday, law enforcement officers responded to the discovery of a body found in nearby Lee County. According to the Lee County Sheriff's Office, the body was of a white woman believed to be in her early to mid-20s.

Iowa Division of Criminal Investigation Special Agent Rick Rahn confirmed later that day that the body was not Mollie Tibbetts, according to The Des Moines Register, although the death did appear to be suspicious.

Tibbett's family continues to hold out hope the college student is still alive. As of Sunday, the reward fund for anyone with information about Tibbetts' whereabouts had climbed to $260,000.

Her mother, Laura Calderwood, told the media during a press conference last week that she hoped the reward would motivate an abductor to release her daughter.

"We believe that Mollie is still alive and, if someone has abducted her, we are pleading with you to please release her," Calderwood said, according to CNN.

While police have not declared the disappearance an abduction, her friends and family say the 20-year-old would not have left on her own.

"She did not just run away," her college roommate Ali Meyer told Dateline according to NBC News. "The last conversation I had with her, we were saying how excited we were to live with each other again."

Her brother Jake Tibbetts described his sister as a really loveable person who never hurt other people.

"She loved to help people, I know that," he told Dateline.

Tibbetts had been studying psychology in college and was working at a day care this summer, her father Rob Tibbetts said.

"She had had a great summer," he told Dateline. "She was very, very happy and optimistic about going back to school."